Google detailed a series of security changes that will be implemented starting next year in a quest to increase the platform's security and possibly even reduce fragmentation within the app ecosystem. As such, beginning with August 2018, Android applications will be required to target a recent API level, and in August 2019, all applications in the Play Store will have to offer 64-bit compatibility. Both of these changes and others are directed at application developers and won't directly affect Android users, however, at the end of the day, these changes are meant to improve the Play Store experience and thus will eventually leave a mark on the entire platform.
Google's roadmap for future changes in the Play ecosystem contains a handful of main steps spanning over the next couple of years. All future Android applications launching beginning with August will be required to target a recent Android API level (26 or higher, corresponding with Android 8.0 Oreo) and future updates to applications that already exist in the Store will also need to target API level 26 or higher beginning with November 2018. Therefore, apps that explicitly declare support for new API behaviors through the 'targetSdkVersion' manifest attribute will also have to advance the 'targetSdkVersion' to a new requirement every year. It's also worth noting that applications that are no longer receiving new updates won't have to meet these new demands, meaning that Android users who happen to utilize older apps on previous Android versions should still be able to do so.
Additionally, starting with early 2018, the Play Store will pair each APK with a small amount of security metadata in order to further verify whether the application was officially distributed by Google Play. No actions will be required om the developers' part in this particular case, as Google will simply adjust the maximum APK size on the Play Store in order to take the small metadata addition into account. Furthermore, all existing applications in the Play Store will be required to offer 64-bit versions beginning with August 2019, and this should theoretically provide improved security as well as higher levels of performance on devices supporting the architecture, should developers take their time to optimize their creations for the said architecture. With these recent changes and the introduction of Project Treble, Google aims to create a less fragmented and secure app ecosystem, all the while providing the ways and means for OEMs to push timely software updates without requiring input from chipset makers.